Air-pump.



J. S. HEMENWAY.

AIR PUMP. 7 APPLICATION FILED MAR.17, 1909.

951,529, Patented M238, 1910.

i I, A.

tr Emma.

.AIB-PUI/IP.

Specification of Letters Patent.

Patented Mar. 8, 1910.

Application filed March 17, 1909. Serial No. 483,923.

To all whom it may concern:

Be it known that I, JUSTIN S. Hindi-1N- \VAY, a citizen of the UnitedStates, residing at River Falls, in the county of Pierce and State ofNisconsin', have invented a new and useful Air-Pump, of which thefollowing is a specification.

This invention relates to air pumps of that type especially designed foruse by students in physical laboratories and the like, and itconstitutes an improvement upon the structure described and claimed inPatent No. 756,630, issued to me on April 5, 1904. I

The object of the invention is to provide a neat and durable device ofthis character constructed of few parts and which cannot readily get outof order, the pump being useful both for compressing and exhausting arr.

A further object is to provide a pump having a piston which alsoconstitutes a valve for controlling the intakes of the pump cylinder,means being utilized whereby this piston, as well as the valves at theoutlets to the cylinder are permitted to work in oil and thus absolutelyprevent leakage at these points.

A further object is to provide a shut-off valve of novel form for use inconnection with the pump and whereby the supply of air to the intakesmay be readily controlled.

Another object is to provide a valve especially designed for use inconnection with large pumps and whereby the resistance offered to theactuation of the piston while being used for compressing purposes, maybe reduced to the minimum.

With these and other objects in view the invention consists of certainnovel details of construction and combinations of parts hereinafter morefully described and pointed out in the claims.

In the accompanying drawings the preferred form of the invention hasbeen shown.

In said drawings :-Figure 1 is a longitudinal section through the casingof the pump, the piston being shown partly in section and the valves andtubes being shown in elevation. Fig. 2 is a plan view of the apparatus,the lever being broken away. Fig. 3 is a perspective view of the cut-01fvalve,

the two parts thereof being shown separated. Fig. 1 is a section of theauxiliary valve designed to be used in connection with large pumps ofthis character. 1

Referring to the figures by characters of reference 1 designates a basesupported in any suitable manner, as upon feet 2, a portion of this baseconstituting a platform 3 on which the operator may stand. Brackets 4are mounted on the end portions of the base at one side of the platform3 and these brackets support the end portions of the pump cylinder orcasing 5, the ends of which are closed by means of screw caps or heads 6having recesses 7 in their inner ends. These recesses constitute seatsfor springs 8 which bear against disks 9 constituting valves fornormally closing the outlet ports 10 of the cylinder. Interior annularshoulders 11 are formed within the end portions of the cylinder 5 andconstitute seats for the valve disks 9, said disks, when bearing uponthese seats, serving to close the ports 10 as clearly indicated at theleft of Fig. 1. The heads 6 are preferably formed with angularextensions 12 which may be engaged by a wrench for the purpose ofadjusting said heads with relation to the cylinder 5.

Extending upwardly from the middle portion of the cylinder 5 and openinginto said cylinder is a housing 13 from the upper end of which extendcars 14. A rock-arm 15 extends through an aperture in the top of thehousing 13 and is fulcrumed upon a pivot pin 16 extending through theears 1 1. The upper or outer end of this arm has a socket 17constituting a seat for the lower end of an actuating lever 18. Thelower end of the rock-arm 15 is rounded as indicated at 19 and projectsinto an opening 20 extending through the middle portion of an elongatedcylindrical piston 21. This piston fits snugly within the cylinder 5 andserves to maintain the bottom of the housing 13 closed at all times.Intake ports 22 are formed in the cylinder 5 adjacent opposite portionsof the housing 13, and these ports are so positioned that when thepiston has reached the limit of its movement in one direction it exposesone of the ports, while the other port 22 is closed thereby. As soon asthe piston begins its return move- .105 ment it closes the previouslyexposed port,

and, immediately prior to reaching the limit of such movement, it opensthe other port 22.

Each of the outlet ports 10 is connected by means of a short tube 23with a hollow globe 24, the two globes communicating through pipes 25with the interior of a globe 26 the outlet 27 of which is connected. toa cross fitting 28, one arm of which is pro vided with a pressure gage29 of the ordinary or any preferred construction. The other arms of thisfitting are provided with nozzles 30 and 31, the nozzle 31 being preferably provided with a cock 32 for control ling the passage of airtherethrough.

The intake ports 22 of cylinder 5 are connected by pipes 33 with a Tfitting 34, one arm of which communicates through a short pipe 35 withthe interior of a valve head 36. This head is preferably circular inform and its flat upper face is provided with a central boss 37 whileformed within this face are three apertures 38, 39 and 40. The aperture38 opens into the head 36 and thus communicates with the pipe 35. Theaperture 40 however opens into one end of a pipe 43 extending radiallyfrom the head 36 and having a vacuum gage 42 mounted thereon. Anotherpipe 41 discharges through the head 46 at the opening 40. The other headof the valve consists of a disk 44 having a central recess 45 for thereception of the boss 37,

and formed within the lower or working face of this disk 44 is anarcuate groove 46 designed to establish communication between any twoadjoining openings 38, 39 and 40. This head 44 may be shifted by meansof arms 47 extending radially therefrom. The disk 44 rests loosely uponthe fiat upper face of the head 36, the meeting faces of the two membersbeing preferably flat and said members being held firmly together byexternal atmospheric pressure. Leakage may be prevented by applying hardoil to the meeting faces of the members beforesaid members areassembled.

.The bell jar 48 used in connection with the pump may be of the usual orany preferred construction, but the base 49 thereof has a centralopening 50 into which projects a radial tube 51 one end of which extendsbeyond the margin of the base. This end of the tube has a flexible hose52 connected to it and this hose may be attached to either of thenozzles 30 or 31 or to either of the pipes 41 and 43, according to theoperation to be performed.

As hasheretofore been stated the piston 21 and the lower portion of arm15 are designed to work in oil. The oil is placed in the housing 13 andin the outlet ports 10 in any preferred manner and may be maintainedatthe same level at these points by connecting the ports 10 by means ofa pipe 53, there being a branch pipe 54 connecting the pipe 53 with theinterior of the housing 13. A globe valve 55 may be arranged within thepipe 54 for shutting off oil from the housing13 if so desired.

When it is desired to compress air within a pressure tank, the parts arear'anged as indicated in Fig. 1, hose 52 being connected to the nozzle30. By oscillating the lever 18 the piston 21 will be caused to reciprocate, and, as it begins one stroke, it will act as a valve to close oneof the intakes 22 and just prior to reaching the limit of such stroke itwill open the other intake 22. The air will thus rush into the cylinder5 and destroy the partial vacuum produced by this movement of thepiston, this air entering the tube 43 and passing from opening 40through groove 46 to the opening 38 from which it travels along thetubes 35 and 33 to the cylinder 5. Upon the return stroke of the pistonthe air in the path thereof will be forced against valve disk 9 so as tounseat it, whereupon the air will pass outwardly through the ports 10and globes 24 and 26 to nozzle 30, and thence into the tank. It will beseen that the pump is double-acting inasmuch as air is forced into thebell at each stroke of the piston. The pressure of air within the bellwill be accurately indicated by the member 29.

Should it be desired to exhaust air from a bell jar 48 the hose isconnected to either tube 41 or tube 43. When it is desired to ascertainthe condition of the partial vacuum produced it is desirable to connectthe hose to the tube 43 on which the indicator 42 is mounted. The valvemember 44 is then adjusted so as to place the openings 38 and 40 incommunication. lVhcn the piston 21 is reciprocated in the mannerhereinbefore described a partial vacuum is produced in the wake thereofduring each stroke until said stroke has been almost completed whereuponthe intake port 22 will be opened and the air will be free to rush intosaid. N

the valves 9 and the piston 21 work in oil,

because this oil serves to positively close any minute openings whichmight otherwise occur and therefore leakage of air past the valves orpiston is prevented.

In the larger types of pumps of this character itis desirable to utilizeauxiliary valves and connections for reducing to the minimum the powernecessary to operate the pump. F or example, during the operation offorcing air into a pressure tank or'the like a partial vacuum. isproduced during the greater portion of each stroke of the piston. This,in addition to the resistance offered by he air being forced, serves togreatly retard the action of the piston. In order to prevent theformation of a partial vacuum during the forcing operation a check valve56 may be arranged within each end portion of cylinder 5 and close tothe valve seat 11, each of these check valves preferably consisting ofan apertured disk 57 normally held by gravity upon its seat 58. Thecasing of the valve is connected by means of a pipe 59 with the intakeport 22. It will be apparent therefore that when the piston 21 isshifted in one direction during the operation of forcing air, the airentering the pump through the tubes or pipes 33 is not held back untilthe piston almost reaches the end of its stroke, but is free to promptlyenter the cylinder and back of the piston through the casing of thevalve 57. During the exhausting action of the pump this auxiliary valvewill have effect only as long as the pressure of the air in the receiveris suiticient to lift the valve. As soon as the air in the receiver hasbecome too rare to open the valves said valves will remain dormant whilethe exhaustion is completed through ports 22.

it is of course to be understood that various changes may be made in theconstruction and arrangement of the parts without departing from thespirit or sacrificing the advantages of the invention.

What is claimed is 1. A pump comprising a cylinder having intakes, therebeing outlets adjacent the ends of the cylinder, valves for normallyclosing said outlets, piston mounted to reciprocate within the cylinderand controlling the intakes, a housing opening into the cylinder andclosed by the piston, said housing and the outlet ports constitutingreceptacles for a sealing liquid.

2. A pump comprising a cylinder having intakes, there being outletsadjacent the ends of the cylinder, valves for normally closing theoutlets, a piston mounted to re ciprocate within the cylinder andcontrolling the intakes, a housing opening into the cylinder and closedby the piston, said housing and the outlet ports constitutingreceptacles for a sealing liquid, and means for maintaining the liquidwithin said housing and the ports constantly at the same level.

8. A pump comprising a cylinder, said cylinder having intakes and outletports, valves for normally closing the outlet ports, a piston mounted toreciprocate within the cylinder and controlling the intakes, a housingopening into the cylinder and closed at the bottom by the piston, saidhousing and the'ou'tlet ports constitutingreceptacles for a sealingfluid, and means mounted to osstrokes, said intakes being maintainedclosed.

at other times by the piston, a housing opening into the cylinder andclosed by the piston, said housing and the outlet ports constitutingreceptacles for a sealing liquid.

5. A pump comprising a cylinder having intakes, there being outletsadjacent the ends of the cylinder, valves for normally closing saidoutlets, an elongated cylindrical piston mounted to reciprocate withinthe cylinder, said piston alternately opening the intakes during thecompletion of its respective strokes, said intakes being maintainedclosed at other times by the piston, a housing opening into the cylinderand closed by the piston, said housing and the outlet ports constitutingreceptacles for a sealing liquid, and means for maintaining the liquidwithin said housing and ports constantly at the same level.

6. A pump comprising a cylinder, said cylinder having intakes and.outlet ports, a housing opening into the cylinder, valves for normallyclosing the outlet ports, a piston for alternately opening the intakesdur ing the completion of its respective strokes, said intakes beingmaintained closed at other times by the piston, and said pistonconstituting the closure for the bottom of the housing, said housing andthe outlet ports constituting receptacles for a sealing fluid, and meansmounted to oscillate within the housing for actuating the piston.

7. A pump comprising a cylinder having a housing thereon and openingthereinto, there belng intake ports adjacent the housing and outletports adjacent the ends of the cylinder, a piston mounted to reciprocatewithin the cylinder, said piston oper ating to alternately open theintake ports during the completion of its respective strokes, meansmounted to reciprocate within the housing for actuating the piston,non-communicating intake pipes, means for establishing communicationbetween either of said pipes and both intake ports, a discharge nozzle,and tubular connections between said nozzle and the outlet ports.

8. A pump comprising a cylinder having a housing thereon and openingthereinto, there being inlet ports adjacent the housing and outlet portsadjacent the ends of the cylinder, valves for normally closing theoutlets, a piston mounted to reciprocate Within the cylinder, saidpiston constituting a closure for the housing and alternately openingthe inlet ports during the completlon of the respective strokes of thepiston, oscillating means within the housing for actuating the piston,said housing and the outlet ports constituting receptacles for a sealingfluid.

9. A pump comprising a cylinder having inlet and outlet ports, a pistonmounted to reciprocate Within the cylinder for alterg nately opening theinlet ports during the completion of the respective strokes of thepiston, and valved extensions for establishing communication between theinlet ports and the end portions of the cylinder.

In testimony that I claim the foregoing as my own, I have hereto affixedmy signature in the presence of two Witnesses.

: JUSTIN S. HEMENVAY. i Vitnesses: I

V. G. SrENoE, H. E. NELSON.

